Technical Field
The present disclosure relates to an electrochromic dimming device and an electrochromic driving device.
Description of the Related Art
Photochromic dimming elements generally control the transmittance by emission of light (e.g., ultraviolet). Unlike photochromic dimming elements, electric dimming elements use electric signals for controlling the transmittance. Electric dimming elements have an advantage that the transmittance is easily controllable by users and is automatically increased in dark places.
As electric dimming elements, liquid crystal elements and electrochromic elements are known, which are applications of liquid crystal materials and electrochromic materials, respectively. Electrochromic elements are known to be transparent when in a neutral state and to show high optical density when carrying particles of titanium oxide or the like. Therefore, electrochromic elements are advantageously used for obtaining high-contrast dimming elements.
Electrochromic elements that reversibly cause oxidation and reduction reactions upon application of a voltage generally contain a colorant which develops and discharges color by the oxidation and reduction reactions. The colorant is generally oxidized or reduced by being applied with a voltage from a driving device.
Conventional electrochromic driving devices generally perform a sequence control and a feedback control when controlling the responsiveness in color development/discharge operations or when retaining a specific density in color development operations. To perform a sequence control and a feedback control, a detection circuit is generally required for detecting electric properties of the electrochromic element, such as pole potential, impedance, injection potential, and discharge potential, as control parameters.